A. Field of the Invention
This invention relates to techniques for monitoring the medical condition of a patient, and, more particularly, to a method and apparatus for monitoring a patient at a remote site from a central station by means of interactive visual communications techniques and devices. While the invention is also suitable for use in any situation where a patient is to be monitored at a site remote from a central station, it is especially suitable to the monitoring and caring for the elderly in the home environment. Thus, the invention can also be said to relate to the field of geriatric care.
B. The Prior Art
1. General Considerations
Modern society with its improvement in living conditions and advanced health care has brought about a marked prolongation of life expectancy. This change has resulted in a dramatic and progressive increase in the geriatric population. A large percentage of the geriatric population needs continuous general, as well as medical, supervision and care. For example, supervision of daily activities such as dressing, personal hygiene, eating and safety as well as supervision of their health status is necessary. Furthermore, the relief of loneliness and anxiety is a major, yet unsolved, problem that has to be dealt with. These and other facets of the management of the ever increasing geriatric population have yet to be successfully addressed and solved.
The creation of retirement facilities and old age homes, as well as other geriatric facilities, provide only a partial solution to the problems facing the geriatric population. The geriatric population, a constantly increasing fraction of society, has become increasingly dependent upon the delivery of home health and general care, which has its own set of challenges and drawbacks.
The notion of ambulatory (home environment) patient care is gaining increased popularity and importance. According to some recently published reports, the number of old aged people receiving home care services under Medicare has shown a 13% annual growth rate and has tripled in 10 years (1978-1988) from 769,000 to 2.59 million. This dramatic shift in patient care from the "sheltered" institutional milieu to the patient's home, work place, or recreational environment is due primarily to a radical change in concepts. That is, specialists in geriatric care tend to keep the aged in their own natural environment for as long as possible. Moreover, the marked increase in the cost of institutional patient care, the important technological advances and the development of medical equipment, and the explosive development in the field of telecommunication are some of the additional factors that may help in creating proper home care for the aged.
Presently, geriatric home care is still in its first stages of development. However, according to some recently published market research reports, the market for home care services and products is booming. Annual spending on home care services is expected to increase from $8.8 billion in 1988 to $16 billion in 1995, while annual spending on home care products will increase from $1.15 billion to $1.86 billion during the same period.
Except for scarce model organizations, home care is carried out either by the patient's family or by nonprofessional help. The monitoring equipment at home care facilities is usually minimal or nonexistent, and the patient has to be transported to the doctor's office or other diagnostic facility to allow proper evaluation and treatment.
Patient follow-up is done by means of home visits of nurses which are of sporadic nature, time consuming and generally very expensive. A visiting nurse can perform about 5-6 home visits per day. The visits have to be short and can usually not be carried out on a daily basis. Moreover, a visiting nurse program provides no facilities for continuous monitoring of the patient and thus no care, except in fortuitous circumstances, in times of emergency. The remainder of day after the visiting nurse has left is often a period of isolation and loneliness for the elderly patient.
The existing home care nursing facilities divert skilled nurses, a scarce commodity, from the hospital environment and uses them in a highly inefficient manner due to the wide dispersion of the patients and the lack of sophisticated diagnostic facilities in the patients'home. Clearly, the practice of visiting nurses leaves much to be desired.
These considerations apply to the general population as well, as the spiraling cost of hospital care has lead to a dramatic increase in the use of outpatient care as a treatment modality.
2. Prior Art Models of Ambulatory Patient Monitoring
One of the areas in which ambulatory patient monitoring is most widely used is out-of-the-hospital surveillance of the cardiac patient. Patients with cardiovascular problems (diseases of the heart and blood vessels) constitute the largest and most important diagnostic and therapeutic challenge facing the authorities responsible for the deployment of health care to the adult and specifically aging population in the U.S. About 15% of the adult population of the industrialized world suffers from hypertension, a major risk factor for atherosclerosis, heart disease, and stroke. Other commonly accepted risk factors such as: elevated blood lipid levels, obesity, diabetes, smoking, mental stress and others are also abundant.
Every year more than 1.5 million people in the U.S. suffer a heart attack. This together with stroke constitutes the number one cause of death in our adult population. More importantly, the majority of cardiac related deaths occur outside of the sophisticated and sheltered hospital environment. Therefore the need for means for ambulatory monitoring of these patients is obvious.
To date the electrocardiogram (ECG) and blood pressure are two main parameters most commonly monitored in the out-of-the-hospital environment. Holter monitoring (continuous 24 hour tape recording of the electrocardiogram) and continuous recording of blood pressure are useful modalities for the evaluation of changes in the cardiovascular system. These, however, are short term monitoring systems that provide only off line information that becomes available at best hours after their recording. Moreover, the hook up should be done by a nurse or technician. Lately, transtelephonic ECG surveillance has been gaining in importance. This system uses small ECG transmitters which allow the transmission of the patients ECG over any telephone line to a diagnostic center. This on-line information system is operative 24 hours a day, 365 days a year. The patient is in direct contact with a highly trained team that can intervene at any time and make real time decisions. The drawback of this system is its communication system, which does not lend itself to prolonged monitoring sessions and does not allow for visual observation of the subject.
A home medical surveillance system is described in U.S. Pat. No. 4,838,275, issued to Lee. This system involves the generation and transmission of health-parameter signals from a patient's home to a central station. However, the described system envisions only two way voice communication between the patient and the observer at the central station. This system does not provide for interactive visual communications between the patient and health care provider, and thus lacks a principal feature and advantage of the present invention.
U.S. Pat. No. 4,524,243 discloses a personal alarm system in which a warning signal is sent to a central monitoring station if the patient's activity level becomes inactive, such as in the case of a medical emergency. This technology is limited in its diagnostic and therapeutic value, and does not, in and of itself, provide for interactive voice or visual communication between the patient and the physician.
Other patents disclose techniques for the transmission of still medical images over a communications line to a remote site. For example, U.S. Pat. No. 4,860,112, issued to Nichols et al., discloses methods and apparatus for scanning medical images such as x-ray images and transmitting the scanned image to a remote location. U.S. Pat. No. 5,005,126, issued to Haskin, discloses a system for picking off an internal analog video signal from imaging diagnostic equipment such as a CAT scanner and transmitting the image to a remotely located physician's station. U.S. Pat. No. 4,945,410, issued to Walling, discloses a satellite communications system for transmission of still medical images from a remote satellite transmission station to a central headquarters. These patents have their own inherent limitations and lack the interactive audio and visual capabilities provided by the present invention. An ambulatory home care and patient monitoring system, combining a long-term monitoring facility, the possibility of visual contact between the patient and health practitioner, and on-line, real time intervention capability has eluded those in the art.
3. Available Home Health Monitoring Devices
There exists, at present, home health care and monitoring products that perform various functions. The simplest include, amongst others, instruments such as self-operated blood pressure devices (sphygmomanometers), blood glucose measuring instruments, automated medication dispensers and others. While these products are designed to be useable by a patient without any assistance, they have no inherent capability of remote monitoring. Moreover, they are often difficult to use by elderly or infirm patients.
The other end of the spectrum includes the development of computer controlled robots that provide an integrated, highly sophisticated, home based monitoring unit. An example of such a device is the HANC (Home Automated Nursing Center) system described in U.S. Pat. No. 5,084,828, issued to Kaufman et al. This patent includes a robot capable of monitoring the patient's vital signs, reminding the patient of his or her medications, dispensing them in due time, and contacting a control center for routine follow-up as well as in emergency situations. This device is generally an unsatisfactory solution to the problem of at-home patient monitoring because it is extremely expensive, unfriendly, impersonal, cumbersome, and lacks interactive communication capabilities between the patient and their physician.
The complex robotic units and home computer are impressive in their capacity, but lack the human contact which is so important in effective geriatric care. The patient's interaction with a machine, as sophisticated as it may be, will always be inferior to the direct human contact. Moreover, these systems are very expensive and will in the foreseeable future be available to only a very small number of patients who can afford them. Moreover, the older population does not adjust easily to computers and robots, and mistakes in their use are frequent. Maintenance and problems and the difficulty in programs in the computerized system make the upkeep more complex. Thus, the currently available techniques for providing home patient monitoring, particularly of the elderly, leave much to be desired.
4. Other Geriatric Health Risks
Additional facts support development of an improved home health care system especially for a geriatric population. For example, falls are a major health problem among the elderly, causing injury, disability and death. One third (some studies suggest half) of those over the age of 65 suffer at least one fall each year. The rate of falling increases to 40% among those who exceed the age of 80. According to the National Safety Council, falls accounted for one-third of the death total for the elderly. Those who survive falls may have restricted activity, soft-tissue injuries, or fractures. It is estimated that up to 5% of falls by elderly persons result in fractures. A similar percent result in soft-tissue injury requiring hospitalization or immobilization for an extended period. It is estimated that hip fractures resulting from falls cost approximately $2 billion in the United States during 1980. Falls are mentioned as a contributing factor to admissions to nursing homes.
The factors leading to falls can be divided into two main groups: environmental factors and medical factors. In spite of the difficulty in the surveillance of patient condition before a fall, almost all researchers share the conclusion that environmental hazards are decreasingly important in causing falls as age increases. A clear correlation between clinical or medical problems and the incident of falls by the elderly has been established. Many of these medical problems of the elderly or infirm can be detected by simple clinical observation. For example gait and balance abnormality may indicate difficulty with neurologic and musculoskeletal functions that may contribute to physical instability. Changes in gait can be identified by the following: slow speed, short step length, narrow stride width, wide range of stepping frequency, a large variability of step length, and increasing variability with increasing frequency.
Thus, there are relatively straight forward techniques which enable diagnosis of a predisposition or likelihood of falls among elderly. However, there is no inexpensive procedure for undertaking such diagnosis or investigating such predisposition in a large patient population wherein the kinematic condition of the patient can be investigated or where the appearance, and reflex activity of the patient can be investigated with ease.